<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Form</title>
</head>
<body>
<table border="1">
    <thead>
    <tr>
        <th>浏览器</th>
        <th>渲染引擎</th>
        <th>JavaScript 引擎</th>
    </tr>
    </thead>
    <tbody>
    <tr>
        <th>Chrome</th>
        <td>Blink</td>
        <td>V8</td>
    </tr>
    <tr>
        <th>Opera</th>
        <td>Blink</td>
        <td>V8</td>
    </tr>
    </tbody>
</table>

<select multiple>
    <optgroup label="Group 1">
        <option value="option1">Option 1</option>
        <option value="option2">Option 2</option>
    </optgroup>
    <optgroup label="Group 2">
        <option value="option3">Option 3</option>
        <option value="option4">Option 4</option>
    </optgroup>
</select>

<label for="username">Username:</label>
<input type="text" id="username" name="username">

<p><input type="text" value="只读内容" readonly></p>
<input type="text" value="禁用内容" disabled>
</body>
</html>